US CBP officers pre-clear travelers in Vancouver on the existing Amtrak route; however, the train is stopped anyway just across the border to give those agents

US CBP officers pre-clear travelers in Vancouver on the existing Amtrak route; however, the train is stopped anyway just across the border to give those agents a reason to exist as well. The existing Amtrak experience is terribly slow - like five hours from Vancouver to Seattle. A high speed rail service would conceivably use pre-clearing as well.